It is well known that open trough roof gutters fill with leaves and other debris causing impaired effectiveness of the gutter as a roof drainage system. Frequently, water accumulates in clogged gutters causing an overflow failure which can damage the building. If the gutters freeze, the expanding water can deform the gutter and may cause it to pull away from the building support. The water may also force its way back up under the shingles or roof covering, causing damage to the roof itself. Thus some form of gutter shield is desirable for separating (straining) debris from the water running off of a roof edge. Ideally, such a shield will not only allow, but encourage water to flow into the gutter while debris is separated and enabled to slide off the outer edge of the shielded gutter.
Some known gutter shields are formed of screen material (e.g., hardware cloth), or expanded metal screening in which a web of metal stock is slit and then drawn or expanded so as to laterally stretch open the slits to form openings for water and yet at the same time to shield the gutter from debris. Such systems, while somewhat effective in guarding against accumulation of larger debris (e.g., twigs and leaves) in the gutters, have openings which are large enough to allow smaller items of debris (e.g., small seeds, “propeller” vanes on seed pods, evergreen “needles” and leaf fragments) to pass through either partly or entirely. If not removed, these materials accumulate and eventually clog the shield and/or the gutter.
Prior art gutter shields that, like the above-described screening, have a rather rough surface texture can become externally clogged because such arrangements allow debris to accumulate on the shield itself thereby blocking water's access to the gutter and rendering it ineffective. In such cases, water can well up about the accumulated debris and migrate under the edge of the roof and/or roof covering causing damage.
U.S. Pat. No. 6,073,398 (Williams; 2000) discloses a gutter cover with a planar back area (14) connected to a curved front portion (18) that leads water by capillary action into the covered gutter. It can be seen that debris (at least larger pieces) generally will not follow the curved portion and will instead wash off the outside edge of the covered gutter. Other examples of capillary action shields with gutter access holes beyond a curved portion include U.S. Pat. No. 5,251,410 (Carey; 1993) and U.S. Pat. No. 4,616,450 (Shouse; 1986).
A problem with designs such as Williams '398, Carey '410, and Shouse '450 is that in a hard rain, water flow is too great and a significant portion of the water will simply shoot outward beyond the outside edge of the covered gutter. In order to address this problem, gutter shields such as those disclosed in U.S. Pat. No. 5,640,809 (Iannelli; 1997) and U.S. Pat. No. 5,557,891 (Albracht; 1996) provide means for slowing down the flow of water. Iannelli '809 provides a substantially planar primary surface (20) that has longitudinal protuberances (35) and a rise (36); and Albracht '891 has a relatively wide horizontal portion (7).
There are also problems with gutter shields that are secured horizontally across the top opening of the gutter, or which have substantially planar or wide horizontal portions. Since debris may not be washed off of such horizontal portions, the weight of accumulated debris on the gutter, which bears the weight of the shield as well as the debris accumulated thereon, can cause the gutter or the shield to collapse and/or pull away from the fascia to which it is attached. Thus, the shield may create more problems than it solves. There is therefore a need for a gutter shield that is effective in preventing the accumulation of debris both in and on top of a gutter, and that allows the debris to fall away or be swept off of the shield by wind and rain.
The prior art contains a number of gutter shields that are sloped downward and outward and which have apertures through the downslope for separating water from debris. The optimum shape of the shield material around and leading into each aperture, and therefore the size, shape and location of an aperture, is the subject of much debate and is often a factor in distinguishing one shield from another. These shapes, etc. affect the water's flow rate, capillary action and sheeting, as well as the size/shape of debris that is filtered out and whether the debris will accumulate on the shield and/or clog its apertures.
Capillary action and sheeting are both effects of surface tension but may effectively work against each other. For example, capillary action results in water being “held” against a surface and “pulled” through an aperture toward which and/or through which the surface leads the water. In opposition to this, water may pass over an aperture if the water is held together by surface tension in a continuous “sheet”. Such a sheet must be effectively broken or perforated in order for any of the water to drain away into an aperture below the sheet. It is also possible for a sheet of water to form on the underside of a sloped surface, thereby forming a barrier to water flow down through the sheet from apertures above it.
U.S. Pat. No. 4,418,504 (Lassiter; 1983) discloses a sloped shield having apertures (19) that are positioned between an upstream arch followed by a trough. U.S. Pat. No. 6,016,631 (Lowrie, III; 2000) discloses a gutter device having a plurality of holes (31), preferably formed by creating a depression (31) in the downslope portion. U.S. Pat. No. 5,271,191 (Vahamaki; 1993) discloses a gutter shield having slotted (24) vanes (26) wherein the vanes are sloped downward at a vane angle (27) relative to the plane of the shield's stock material. U.S. Pat. No. 6,151,837 (Ealer, Sr.; 2000) discloses a perforated sheet gutter screen comprising a sheet metal member with a generally smooth top surface and a plurality of channels (54) and slots (56), wherein each channel extends downward and away from the top surface and has a lower end that defines a lower portion of the periphery of one of the slots, and has a concave profile such that an upper, leading edge of the channel is curved substantially along its full length.
In light of the abovedescribed problems and defects in the prior art, it is an object of the present invention to overcome these defects by providing a gutter shield that not only separates even small debris from rainwater, but furthermore resists accumulation of the debris on the gutter shield, and even further encourages the flow of water through the shield and into the shielded gutter even when water is flowing rapidly and tending to “sheet” above and/or below the shield.
Controlling water flow (down the roof, into the gutter) and preventing debris accumulation can be particularly challenging in a roof valley area. There may be increased water flow in the valley (two surfaces are dumping water into the valley, as opposed to only one). Also, with two surfaces joining one another, the structural/geometric variations can be significant, as contrasted with a simple single roof surface sloping into a gutter section.
U.S. Pat. No. 1,986,383 (Usinger; 1935) discloses a gutter miter for carrying a gutter or eaves trough into an angle formed by roof sections. The gutter miter is constructed to promote distribution of the water from the valley to the gutters provided for the roof sections. Two roof sections (a) meet at an angle and are provided with a valley gutter (b).
U.S. Pat. No. 6,883,760 (Seise; 2005) discloses a rain gutter cover system (10). The system (10) is configured for directably collecting rain water running off of the roof (R) of a building (B) while substantially preventing undesired debris from entering the gutter (16). The system (10) broadly includes a gutter assembly (12) and a cover assembly (14) coupled to, and covering, the gutter assembly (12). The cover assembly (14) includes a one piece screen (20) and a plurality of fluted perforations (22) formed in the screen (20). The fluted perforations (22) are each particularly configured to draw water through the screen (20) without allowing undesired debris through the screen (20) and each includes a channel (40) recessed into the screen (20) and a corresponding hole (42) defined in the downhill end of the channel (40). The screen (20) is generally S-shaped and defines an upper guard section (24), a bull-nose ledge (26), an intermediate siphoning section (28), a secondary bend (30), and a lower drainage section (32). A valley segment (210) of the system is also disclosed and includes a plurality of bull-nose ledges (212, 214, 216, 218 and 220), each guarding a plurality of fluted perforations (222) along the valley of a roof. An alternative valley configuration is also disclosed: The rain gutter cover system (300) utilizes a generally flat valley segment (302) with a single bull-nose ledge (304) at the gutter. The segment (302) includes a plurality of fluted perforations (306) that siphon water through the screen (302) and onto the valley flashing below. Unlike the corner gutter assembly (202), the gutter assembly (308) includes an angled miter-boxed corner (310) that provides increased space between the fascia board and an outermost gutter edge (312) for positioning the bull-nose ledge (304).
U.S. Pat. No. 5,623,787 (Ali; 1997) discloses a resilient mesh elongated guard for the valley between adjoining angled sections of a tile roof wherein the guard is bent into a convex shape and positioned into the valley with the lateral edges of the guard engaging the sides of the opposed faces of the tile.
Glossary & Definitions
Unless otherwise noted, or as may be evident from the context of their usage, any terms, abbreviations, acronyms or scientific symbols and notations used herein are to be given their ordinary meaning in the technical discipline to which the disclosure most nearly pertains. The following terms, abbreviations and acronyms may be used throughout the descriptions presented herein and should generally be given the following meaning unless contradicted or elaborated upon by other descriptions set forth herein. Some of the terms set forth below may be registered trademarks (®).    Dormer A vertical window built into the slope of a pitched roof.    Eaves The area just below the lower end of the roof—includes the fascia, soffit and guttering.    Fascia The vertical board secured to the ends of the rafters under the lower end of the roof to which the guttering is normally fixed—traditionally timber, nowadays usually uPVC.    Flat Roof A roof which has negligible slope, usually covered in felt, metal, or other material which is impermeable to water.    Gable The vertical wall at the end of a pitched roof, an inverted ‘V’.    Gable Roof A gable (or gabled) roof is a triangular roof, with flat (vertical) ends.    Gutter A rain gutter (also known as eaves trough, guttering or just gutter) is a narrow channel, or trough, forming the component of a roof system which collects and diverts rainwater shed by the roof. In many buildings, the purpose of this diversion is to prevent water from falling off the roof edges. This uncontrolled water can cause structural damage to the walls and/or the foundation of a building. Another purpose of rain guttering can be to harvest rainwater for household or garden use.            Rain gutter can be constructed from a variety of materials, including galvanized steel, painted steel, copper, painted aluminum (also known as Seamless Aluminum), PVC (and other plastics), concrete, stone and wood.        Water collected by a rain gutter is fed, usually via a downpipe, into a collection system. A collection system can be either a rainwater tank, a storm water main, or a sewer main (depending upon local codes). In some locations where collection to a main is not feasible, the water is dispersed into a storm water pit or cistern. The rain gutter on houses that have overhanging trees can become blocked with leaves over time and can cause a fire hazard, particularly in bushfire areas. Various styles of mesh and other perforated materials have been applied as leaf guard to help prevent this problem from occurring. In some areas with high bushfire danger, some type of leaf guard is mandated by the building code.        Clogged gutters can cause water leakage into the house as the water backs up. Clogged gutters can also lead to stagnant water build up which allows mosquitoes to breed and also allow grasses and weeds to grow in the gutter.        Gutters in colder climates also suffer the effects of freezing. However this can be mitigated through the use of heating cables placed in the trays that become activated in freezing weather.            Hip A sloping ridge formed by the junction of a pitched roof and a hip end.    Hipped Roof A hip (or hipped) roof is a type of roof where all sides are sloped    Lap Joint In woodworking, or metal fitting, a lap joint describes a technique for joining two pieces of material by overlapping them. A lap may be a full lap or half lap. In a full lap, no material is removed from either of the members to be joined, resulting in a joint which is the combined thickness of the two members. In a half lap joint, material is removed from each of the members so that the resulting joint is the thickness of the thickest member. Most commonly in half lap joints, the members are of the same thickness and half the thickness of each is removed.    Ridge The horizontal line at the top of a pitched roof—applies whether there is a sloping roof on both sides (a Duo ridge), or if there is just one (a Mono ridge).    Shingles Roof shingles are a roof covering consisting of individual overlapping elements. These elements are normally flat rectangular shapes that are laid in rows without the side edges overlapping, a double layer is used to ensure a waterproof result. Shingles are laid from the bottom edge of the roof up, with the bottom edge of each row overlapping the previous row by about half its length.            An asphalt shingle is a type of roof shingle. They are one of the most widely used roofing covers due to the fact that they are relatively inexpensive and fairly simple to install. Two types of asphalt shingles are used: organic and fiberglass or glass fiber. Organic shingles are generally paper (felt) saturated with asphalt to make it waterproof, then a top coating of adhesive asphalt is applied and the ceramic granules are then embedded. A portion of the granules contain leachable copper or more often tin to prevent moss growth on the roof. Organic shingles contain around 40% more asphalt per square (100 sq. ft.) than fiberglass shingles which makes them weigh more and gives them excellent durability and blow-off resistance. Shingles are judged by weight per square.        Fiberglass shingles have a glass fiber reinforcing mat manufactured to the shape of the shingle. The mat is then coated with asphalt which contains mineral fillers. The glass fiber mat is not waterproof by itself and is a wet laid fiberglass mat bonded with urea-formaldehyde resin. It's used for reinforcement. The asphalt makes the fiberglass shingle waterproof.        Shingles have been made of various materials such as wood shingle, slate shingle, asbestos-cement, bitumen-soaked paper covered with aggregate (asphalt shingle) or ceramic.            Soffit The horizontal board used to seal the space between the back of the fascia and the wall of the building—traditionally timber, or cement board—nowadays usually uPVC with air vents.    Valley The internal angle formed where adjacent pitched roofs meet. Traditionally zinc, lead, tin, or galvanized sheeting was formed on site to create a water channel downwards, nowadays pre-shaped valley channels are available. The shape may be a simple V following the roof lines, or may have a secondary ridge (e.g., inverted V) running along the centerline of the valley. A “laced” valley covering utilizes reasonably flexible shingles (e.g., asphalt) to form the water channel by interleaving rows of shingles so that they overlap. For example, the first row of shingles on the right will be laid across the valley to end 12 inches to the left of the valley centerline. Then the first row of shingles on the left will be laid across the valley, and over the right-hand end shingle, to end 12 inches to the right of the valley centerline. The second and subsequent rows are laid the same way. Thus each subsequent right-hand row end will overlap the previous left-hand row end when it crosses the valley centerline, and each left-hand row end will overlap the right-hand row end of the corresponding row.    Verge The wall (or rafter) under the edge of a roof where it tops a gable end. The sides of the tiles down the verge were traditionally cemented, nowadays closing strips are available.